if 5 > 12:
    print("5 is greater than 2")
    print("222")
else:
    print("5 is less than 2")
    age = 30
    if age < 18:
        print("you are underaged")
    elif age >= 18 and age < 30:
        print("you are young")
    elif age >= 30 and age <= 45:
        print("you are middle")
    else:
        print("you are old")

    year = int(input("enter year:"))
    if (year % 4 == 0 and year % 100 != 0 or year % 400 == 0):
        print("%d是闰年" % year)
    else:
        print("%d不是闰年" % year)
a = int(input("enter a:"))
b = int(input("enter b:"))
c = int(input("enter c:"))
if a > b:
    if a > c:
        print("a is greatest")
    else:
        print("c is greatest")
else:
    if b > c:
        print("b is greatest")
    else:
        print("c is greatest")

num1 =float(input("enter num1:"))
num2 =float(input("enter num2:"))
op=input("请输入运算符：")
if op=="+":
    print(num1+num2)
elif op=="-":
    print(num1-num2)
elif op=="*":
    print(num1*num2)
elif op=="/":
    print(num1/num2)
else:
    print("输入错误")
# 1


